1. Feed the cat girl in the alley until she's immobile or turn her over to the lab. (This gets you the flavor enhancer).
2. Buy the BE, the Hyper and AE vials from the Shadowed Curios.
3. Go to the Buffet and fatten the maid waitress to the point you can give her the AE, then come back (This gets you the wagyu beef).
4. Go to the Sweet Cravings and fatten the donut girl to the point you can give her the BE, then come back (This gets you the perfect bagel).
5. Win all of the hotdog eating contests with the pink short haired girl (This gets you a packet of greens).
6. Fatten the fairy (this gets you the fairy dust).
7. Get the pills to fatten Diane, then come back to the Supermarket (I think this gets you an ingredient, but I could be wrong.).
8. Give the Hyper vial to your black-haired coworker. (This is in case this is where you get the ingredient and not the Supermarket. Either way, you get six ingredients.).
9. Go the Shadowed Curios and perform some black magic.